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arXiv · 1705.07802

On the structure of the Wadge degrees of BQO-valued Borel functions

Takayuki Kihara·Antonio Montalbán
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Abstract

In this article, we give a full description of the Wadge degrees of Borel functions from $ω^ω$ to a better quasi ordering $\mathcal{Q}$. More precisely, for any countable ordinal $ξ$, we show that the Wadge degrees of $\mathbfΔ^0_{1+ξ}$-measurable functions $ω^ω\to\mathcal{Q}$ can be represented by countable joins of the $ξ$-th transfinite nests of $\mathcal{Q}$-labeled well-founded trees.

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Takayuki Kihara, Antonio Montalbán. 2017-05-22. On the structure of the Wadge degrees of BQO-valued Borel functions. https://arxiv.org/abs/1705.07802

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